The present invention relates generally to wireless communication systems, and more particularly, to a method and an apparatus for verifying the position of a mobile station.
A wireless communication system is a complex network of systems and elements that includes many mobile stations (such as radiotelephones, pagers, and the like) communicating with a wireless infrastructure. A typical wireless infrastructure includes several base transceiver stations, base station controllers and a call controller or switch. The base transceiver stations provide a radio link to each mobile station. The base station controllers control communication as well as manage operation and interaction of the base transceiver stations. The call controller or switch routes calls within the wireless communication system and links the system to a landline or public switch telephone network (xe2x80x9cPSTNxe2x80x9d). A wireless communication system may also include a position estimation system to determine the location of a particular mobile station. Examples of such position estimation systems include a celestial system, such as a global positioning system (xe2x80x9cGPSxe2x80x9d), and a terrestrial system, such as forward link trilateration (xe2x80x9cFLTxe2x80x9d).
A mobile station may determine its position using a position estimation system and, then, provide position information corresponding to its position to the wireless infrastructure. The wireless infrastructure may use the position information for providing communication service, such as mobile commerce, and for billing purposes, such as location-based billing. The wireless infrastructure may query the mobile station or the mobile station may autonomously report its position.
Damage to the mobile station, wireless infrastructure or other network equipment may cause the mobile station to report an erroneous position to the wireless infrastructure. Also, the mobile station may report an erroneous position due to its environment, e.g., erroneous signals caused by obstructions and buildings in its vicinity. Thus, the mobile station may report an erroneous position to the wireless infrastructure and, as a result, calls to and from the mobile station may be billed incorrectly or provide faulty location services.
In addition to system damage, a wireless communication system may have inaccurate information about the location of one or more of its mobile stations for other reasons. Location fraud may cause the mobile station to report an erroneous position to the wireless infrastructure. A fraudulent user may modify the mobile station to always report a position within its home coverage area even when the mobile station is outside of its home coverage area. The fraudulent user may do so to avoid a higher rate that is charged for usage outside of his or her home coverage area. Location information reported by a mobile station may also be inaccurate due to network to mobile station latency or stale reported positions.
It is desirable to have a wireless communication system that knows the position of its mobile stations with reasonable accuracy. It is particularly important for the wireless infrastructure to have accurate information about the position of the mobile stations so that the wireless infrastructure can provide communication services properly and bill for those services correctly. Otherwise, calls may provide faulty location services or may be billed incorrectly because the wireless infrastructure has incorrect information regarding the position of the mobile stations. Therefore, a need exists for an improved method and apparatus for verifying the position of a mobile station in a wireless communication system.
The present invention is directed to a method for verifying a position of a mobile station in a wireless communication system. The system monitors the position of the mobile station to determine whether the mobile station is located within a checkpoint area. If the mobile station is located within a checkpoint area, then the system generates a result by comparing a mobile station position to a checkpoint position. The mobile station position is a particular position of the mobile station when it is within the checkpoint area, and the checkpoint position is a position that corresponding to the checkpoint area. The system then determines whether the generated result exceeds a predetermined error tolerance. If the result exceeds the predetermined error tolerance, then the system indicates an error associated with the position of the mobile station.
The present invention is also directed to a method for verifying a position of a mobile station in a wireless communication system based on at least two mobile station positions, preferably derived from different location techniques. The system monitors the position of the mobile station to determine whether the mobile station is located within a checkpoint area. If the mobile station is located within a checkpoint area, then the system generates a first result by comparing a first mobile station position to a checkpoint position and a second result by comparing a second mobile station position to the checkpoint position. Each mobile station position is a particular position of the mobile station when it is within the checkpoint area, and the checkpoint position is a position that corresponding to the checkpoint area. The system then determines whether either (or both) of the first and second results exceeds a predetermined error tolerance. If at least one of the results exceeds the predetermined error tolerance, then the system indicates an error associated with the position of the mobile station.
The present invention is further directed to a wireless communication system for verifying a position of a mobile station. The system comprises a memory portion, a position circuit, and a processor coupled to the memory portion and the position circuit. The memory portion stores a checkpoint position corresponding to a checkpoint area. In response to a detection that the mobile station is within the checkpoint area, the position circuit generates a mobile station position of the mobile station. The processor compares the mobile station position to the checkpoint position to generate a result. If the result exceeds a predetermined error tolerance, then the processor indicates an error associated with the position of the mobile station.
The present invention is still further directed to a wireless communication system for verifying a position of a mobile station. The system comprises a memory portion, a position circuit, and a processor coupled to the memory portion and the position circuit. The memory portion stores checkpoint parameters corresponding to a checkpoint area, and the position circuit generates a mobile station position of the mobile station. The processor determines whether the mobile station is within the checkpoint area based on the mobile station position. The processor also determines whether the mobile station position is accurate based on the checkpoint parameters and one or more error checking routines.